Alkyl tin



United States Patent 3,059,012 ALKYL TIN Ingenuin Hechenbleikner and Kenneth R. Molt, Cincinnati, Ohio, assignors to Carlisle Chemical Works, Inc., Reading, Ohio, a corporation of Ohio No Drawing. Filed Feb. 23, 1960, Ser. No. 10,082 14 Claims. (Cl. 260-4297) The present invention relates to the preparation of tetraaliphatic hydrocarbon tin compounds.

The present commercial process for preparing tetraalkyl tin compounds is the Grignard process, e.g. reacting stannic chloride with butyl magnesium chloride to form tetrabutyl tin. The Grignard process has serious disadvantages and limitations in that the reaction is diflicult to control on a large scale and is both laborious and time consuming. In addition, the process uses ether as a solvent. Ether is difficult to handle and recover and increases the overall cost of manufacture of the tetraalkyl tin.

It has also been proposed in Johnson Patent 2,570,686 to prepare tetraaryl tin compounds or mixed aryl-alkyl tin compounds by a two-stage reaction by first reacting an aryl monohalide with finely divided sodium in the presence of an inert solvent at a temperature not over 50 C. to form an aryl sodium compound and then in a second stage adding a compound having the formula R SnCl to the foregoing mixture at a temperature up to 50 C. X has a value of 0 to 3 and y is 4-1:. This procedure has the disadvantage that the yields of the desired tetrahydrocarbon alkyl are low. The highest yield stated to be attainable is about 65%. Additionally, if temperatures above 50 C. are tried there is an increase in byproduct formation. In fact, it has generally been thought that the sodium process for preparing tetrahydrocarbon tin compounds is unsatisfactory for the production of tetrahydrocarbon tin compounds commercially due to the low yields and undesirable lay-products.

It has been proposed to react a monohalogenated hydrocarbon, stannic chloride anrd metallic sodium at a temperature from 55 C. up to a point just short of the melting point of sodium in Harris Patent 2,431,038. The maximum yield of tetrahydrocarbon tin obtained by this process, however, was only 66.5% of theory.

Accordingly, it is an object of the present invention to prepare tetra aliphatic hydrocarbon tin compounds using sodium in increased yields and in a manner which can compete commercially with the Grignard process.

Another object is to reduce by-product formation in preparing tetra aliphatic hydrocarbon tin compounds using sodium.

An additional object is to devise a safer procedure for preparing tetra aliphatic hydrocarbon tin compounds.

A further object is to form sodium dispersions more easily in preparing tetra aliphatic hydrocarbon tin compounds.

A still further object is to eliminate the problem of sol vent recovery in preparing tetra aliphatic hydrocarbon tin compounds.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications Within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

It has now been found that these objects can be attained by reacting sodium in the form of a dispersion in an inert diluent of particles having a diameter of 1-100 Patented Oct. 16, 1962 microns, preferably 1-20 microns, with a mixture of RX and R SnX Where R is an alkyl, alkenyl or aralkyl group such as methyl, ethyl, n-butyl, n-hexyl, n-octyl, 2-ethylheXyl, tertiary butyl, decyl, dodecyl, tetradecyl, octadecyl, allyl, oleyl, vinyl or benzyl and X is a halogen of atomic weight at least 35, e.g. chlorine, bromine or iodine; y is an integer from 1 to 3, preferably 2 and z is an integer which is 4-y. In the above formulae both Rs can be the same or different. If the two Rs are the same a simple tetrahydrocarbon tin compounds results while if the two Rs are different then a mixed tetra hydrocarbon tin compound results. The two Xs can be the same or different. Preferably, both Xs are chlorine.

The reaction can be carried out at a temperature of 0 C. or below e.g. 20 C. up to just below the melting point of sodium. Preferably, the temperature is about 70 C.

For best results, the sodium should be dispersed in a compound having the formula R Sn where R is alkyl, alkenyl or aralkyl of the type previously defined. 'Ihe Rs can be the same or difierent. The use of the R Sn compound has several important advantages over other inert diluents such as hydrocarbons for example. In the first place, the R Sn compounds are safer to handle from the standpoint of fire and explosion hazards. In the second place, they make it possible to form sodium dispersions more easily, e.g. sodium is dispersed in the R Sn compound times more readily than in aliphatic hydrocarbon diluents. The use of the R Sn compounds eliminates the problem of solvent recovery since they are the products which are obtained by the reaction.

Less preferably, it is also possible to use inert aliphatic hydrocarbons as diluents alone or in addition to the R Sn compounds.

As the compound having the formula RX there can be employed materials such as methyl chloride, ethyl chloride, n-butyl chloride, n-butyl bromide, n-butyl iodide, sec. butyl chloride, tertiary butyl chloride, n-amyl chloride, n-hexyl chloride, n-octyl chloride, 2-ethylhexyl chloride, dodecyl chloride, octadecyl chloride, octyl bromide, vinyl chloride, allyl chloride, oleyl chloride, oleyl iodide, benzyl chloride, benzyl bromide and benzyl iodide.

As the R SnX compound there can be used methyl tin trichloride, n-butyl tin trichloride, see-butyl tin trichloride, octadecyl tin trichloride, butyl tin tribromide, butyl tin triiodine, allyl tin trichloride, oleyl tin trichloride, vinyl tin trichloride, dimethyl tin dichloride, di n-butyl tin dichloride, sec-butyl tin dichloride, tertiary butyl tin dichloride, di-octyl tin dichloride, di-octadecyl tin dichloride, di-butyl tin dibromide, di n-butyl tin diiodide, diallyl tin dichloride, divinyl tin dichloride, dioleyl tin dichloride, butyl octyl tin dichloride, methyl octadecyl tin dichloride, di benzyl tin dichloride, trimethyl tin chloride, tri n-butyl tin chloride, tri see-butyl tin chloride, tri tertiary butyl tin chloride, tri n-butyl tin bromide, tri n-butyl tin iodide, tri octyl tin chloride, tri octadecyl tin chloride, tri oleyl tin chloride, trivinyl tin chloride, trivinyl tin bromide, triallyl tin chloride, tribenzyl tin chloride, methyl butyl octyl tin chloride, etc.

a As the R Sn compound for the inert diluent thus can be used, materials such as tetramethyl tin, tetraethyl tin, tetrapropyl tin, tetraisopropyl tin, tetra n-butyl tin, tetra see-butyl tin, tetra tertiary butyl tin, tetra hexyl tin, tetra octyl tin, tetra 2-ethylhexyl tin, tetra decyl tin, tetra tetradecyl tin, tetra octadecyl tin, tetra oleyl tin, tetra benzyl tin, tetra allyl tin, tetra vinyl tin, di butyl di octyl tin, dimethyl dibntyl tin, methyl ethyl propyl butyl tin, etc.

The R 811 compounds which are prepared by the present invention are the same as those listed above as inert dilucuts and as previously set forth preferably the R Sn compound selected as the diluent is the same as the R 811 3 compound which is prepared in carrying out the process.

Any iner-t liquid hydrocarbon diluent can be employed e.g. aliphatic, including cycloaliphatic, saturated and unsaturated hydrocarbons such as pentaue, hexane, heptene- 2, cyclohexene, cyclohexane, octane, decane, decahydronaphthalene, kerosene, etc. The hydrocarbon can be normal or branched chain. While aromatic hydrocarbons, e.g., benzene, toluene and xylene can be utilized, preferably they are avoided since they have a tendency to react with sodium alkyls and hence result in by-product formation.

In order to make the sodium dispersion, preferably the sodium is mixed with the inert diluent, e.g., tetrabutyl tin, and then heated to ll20 C. in an inert atmosphere to melt the sodium. The mixture of sodium and diluent, e.g., tetrabutyl tin, is rapidly agitated and in a matter of 1520 seconds, the sodium is dispersed into very small particles (120 microns in diameter) which do not coalesce when the dispersion is cooled to below the melting point of the sodium.

By comparison, a sodium dispersion made in a similar manner using a hydrocarbon such as petroleum naphtha in place of tetrabutyl tin requires 5 to 10 minutes of agitation to achieve the same particle size.

7 The fact that tetra alkyl tins can be used as inert diluents for dispersing sodium is surprising since one might expect the following type of reaction to occur:

This reaction is known to take place with tetramethyl tin and sodium in liquid ammonia. However, tests have proven that such a reaction does not occur to any measurable extent in the present process.

Once the sodium dispersion is formed, e.g. in tetrabutyl tin, it is preferably cooled to about room temperature C.) and a solution of the R SnX compound, e.g. dibutyl tin dichloride, in the RX compound, e.g. butyl chloride, is added in such quantities as to satisfy the stoichiometry of the equation:

A small amount, e.g. 5% of the RX compound, e.g. butyl chloride, can be added in advance if desired.

It is preferable that the RX, R SnX and sodium be used in stoichiometric amounts to simplify the recovery problem although an excess of one or two of the three reactants can be used. 7

' When the reaction is completed, the reaction mixture consists primarily of the R Sn, e.g. (C H Sn and sodium chloride. Water is added to dissolve and thereby remove the sodium chloride. After separating and removing the water layer, the product layer is stripped of moisture by heating under vacuum. Since the dispersingmedium used in the reaction is the same as the product formed by the reaction, there is no need for separation.

The dibutyl tin dichloride used as the tin source for forming the tetrabutyl tin in the above reaction can be obtained in conventional fashion by disproportionation with stannic chloride according to the equation:

thus, half of the tetrabutyl tin formed is returned to the process to prepare the starting material.-

As previously pointed out, the particle size of the sodium is critical, being 1-100 microns, preferably not over 20 microns. Thus, when utilizing hydrocarbons as the dispersing medium and a sodium particle size of 1-20 microns' diameter, yields of from 96 to 98% of tetraalkyl tin are obtained while under the same conditions but utilizing sodium sand grains about 1 mm. in diameter the best yield is 88.8%. The reduction in particle size of the sodium, furthermore, did not increase the formation of byproducts, but instead reduced the formation of such materials.

When using a R Sn compound as the dispersing medium the maximum amount of sodium in the dispersion is of the R Sn-Na mixture by weight. There is no minimum amount of sodium, but as the amount of sodium used is reduced, the cost of the process is increased.

In place of using hydrocarbons or R Sn compounds alone as dispersing mediums for the sodium, there can be used a mixture of one or more hydrocarbons with one or more R Sn compounds, wherein R is defined as above. For example, sodium may be dispersed in a mixture of naphtha and tetrabutyl tin, thus gaining some of the virtues of using the tetrabutyl tin (formation of dispersion in less time and with less agitation) while employing smaller quantities of the relatively expensive tetrabutyl tin. More preferably a highly concentrated dispersion of sodium can be made in tetrabutyl tin and then this mixture diluted with naphtha to the desired level for subsequent reaction.

Gaseous hydrocarbons, e.g. butane and pentane which normally as gases at the melting point of sodium, can be .used if super atmospheric pressure is exerted to keep them liquid.

Generally, an inert atmosphere, e.g. nitrogen, argon or helium is employed. Unless otherwise stated, all parts and percentages are by weight. In the examples in determining the percentage yield of product, the weight of the added tetrahydrocarbon tin was first subtracted from the total product.

EXAMPLE 1 Tetra n-Butyl Tin Sodium (138 gms., 6.0 mols) and tetra n-butyl tin (400 gms., chlorine content 0.3% 'as impurity resulting from the formation of the tetrabutyl tin) were charged into a 2 liter flask and heated to 110 C. under an atmosphere of nitrogen. After the sodium was melted, the mixture was vigorously agitated for 20 seconds using a Premier Mill Laboratory Dispersator. Microscopic examination of a sample of the dispersion diluted with mineral oil, revealed no particles larger than 20 microns in diameter with most of the particles falling into the 3-10 micron range. After cooling to 20 C., a solution of di n-butyl tin dichloride (456 gms., 1.5 mols) in n-butyl chloride (306 gms., 3.3 mols) was slowly added to the sodium dispersion. A cooling bath was used to maintain the temperature at 20- 30 C. after completing the addition, the reaction mixture was stirred for two hours at 20-30 C. One liter of water was then added to dissolve the sodium chloride. After settling, the Water layer was removed and the organic product layer was stripped of moisture and excess n-butyl chloride by heating to 150 C. under 20 mm. pressure. The n-butylchloride, after drying, can be reused in preparing subsequent batches. The tetra n-butyl tin was recovered as a pale yellow liquid in an amount of 905 gms.

' containing 0.3% chlorine as an impurity and 34.4% tin (theoretical 34.2% tin). The yield was 97.2%. Without further purification the product was suitable for use as a dispersing medium in preparing subsequent batches of the tetra n-butyl tin.

The tetra n-butyl tin also was used to prepare dibutyl tin dichloride in the following manner- One mol (347 gms.) of the tetra n-butyl tin was reacted with one mol.

EXAMPLE 2 Tetra n-Octyl Tin Sodium (92 gms.,'4.0 mols) and tetra n-octyl tin 400 gms., chlorine content 0.21%) were charged into a 2 liter flask and heated to 110 C. under an atmosphere of nitrogen. After the sodium Wasmelted, the mixture was subamination of the dispersion revealed that the particles of sodium ranged from 1 to 11 microns in diameter. After cooling to 30 C., a solution of di n-octyl tin dichloride (416.1 gms., 1.0 mol) in n-octyl chloride (327 gms., 2.2 mols) was slowly added to the sodium dispersion. A cooling bath was used to maintain the temperature at 25- 35 C. After completing the addition, the reaction mixture was stirred for one hour at 25-35" C. Water (700 gms.) was added to dissolve the sodium chloride. After settling, the water was removed and the product was stripped of moisture and excess n-octyl chloride by heating to 170 C. under 20 mm. pressure. The tetra n-octyl tin (961 gms.), a light amber liquid containing 0.15% chloride (as an impurity) and 20.7% tin (20.6% theoretical) was obtained in 98.0% yield.

Disproportionation of this product with an equal molar amount of tin tetrachloride for 4 hours at 190-210 C. gave di n-octyl tin dichloride (M.P. 39-43 C., chlorine 17.2% theoretical 17.01%) in 95.1% yield.

EXAMPLE 3 Tetra (Z-Ethyl Hexyl) Tin Sodium (92 gms., 4.0 mols) and tetra (2-ethyl hexyl) tin (400 gms. chlorine 0.1%) were charged to a 2 liter flask and heated to 110 C. in an atmosphere of nitrogen. After the sodium was melted, the mixture was vigorously agitated for 30 seconds using the mill of Example 1. The particle size of the sodium in the dispersion ranged from 1 to 15 microns in diameter. After cooling to 20 C., a solution of di (Z-ethyl hexyl) tin dichloride (416.1 gms., 1.0 mol) in 2-ethyl hexyl chloride (327 gms., 2.2 mols) was slowly added to the sodium dispersion. A cooling bath was used to maintain the temperature at 20-30 C. After completing the addition, the reaction mixture was stirred for one hour and then diluted with 700 gms. of water. The product layer was stripped of moisture and excess 2-ethyl hexyl chloride by heating to 170 C. under 20 mm. pressure. The tetra (Z-ethyl hexyl) tin was obtained as an amber oil in an amount of 935 gms. (93.6%) having chlorine containing compounds as impurities in an amount equivalent to 0.09% chlorine.

Disproportionation with tin tetrachloride as in Example 2 gave a 92.8% yield of di (2-ethy1 hexyl) tin dichloride (chlorine 17.1% theory 17.01%).

EXAMPLE 4 T etrabenzyl Tin Sodium (138 gms., 6.0 mols) and tetrabenzyl tin (500 gms. chlorine content 0.41%) were charged to a 2 liter flask and heated to 110 C. under an atmosphere of nitrogen. After the sodium was melted, the mixture was vigorously agitated for 25 seconds using the mill of Example 1. The particle size of the sodium in the dispersion ranged from 1 to 20 microns in diameter. After cooling to 45 C., a solution of dibenzyl tin dichloride (558 gms., 1.5 mols) in benzyl chloride (418 gms., 33 mols) was slowly added to the sodium dispersion. A cooling bath was used to maintain the temperature at 45-55 C. One liter of warm water (60 C.) was slowly added to dissolve the sodium chloride. After settling and removing the water layer, the product was stripped at 170 C. and 20 mm. to obtain the tetrabenzyl tin in excellent yield.

EXAMPLE 5 Tetra n-Batyl Tin Sodium (138 gms., 6.0 mols) and VM and P naphtha (400 gms.) were charged to a 2 liter flask and heated to 110 C., under an atmosphere of nitrogen. After the sodium was melted the mixture vigorously agitated for 5 minutes using the mill of Example 1. Microscopic examination of the dispersion revealed sodium particles of from 1 to 25 microns diameter with about 80% falling in the 4 to 12 micron range. After cooling to 20 C., a solution of di n-butyl tin dichloride (456 gms., 1.5 mols) 6 in n-butyl chloride (306 gms., 3.3 mols) was slowly added to the sodium dispersion. A cooling bath was used to maintain the temperature at 70-30 C. After completing the addition, the reaction mixture was stirred for 2 hours at 20-30 C. One liter of water was slowly added to dissolve the sodium chloride. After removing the water layer, the product layer was stripped of naphtha and excess butyl chloride by heating to 170 C. at 20 mm. The tetra n-butyl tin was obtained as a pale amber liquid in an amount of 504.8 gms. (97.0% of theory) and contained 34.6% tin (34.2% theory) and 0.4% chlorine.

One mol (347 gms.) of this tetra n-butyl tin was reacted with one mol (260 gms.) of tin tetrachloride for 3 hours at 240 C. to form 578 gms. (95.2%) of di n-butyl tin dichloride (M.P. 37-42" C., chlorine 23.5%, theory 23.3

EXAMPLE 6 Tetra rt-Octyl Tin Sodium (92 gms., 4.0 mols) was dispersed in VM and P naphtha (400 gms.) as in Example 5. Particle size of the dispersed sodium ranged from 1 to 14 microns diameter. After cooling to 25 C., a solution of di n-octyl tin dichloride (416.1 gms., 1.0 mol) in n-octyl chloride (327 gms., 2.2 mols) was slowly added to the sodium dispersion. A cooling bath was used to maintain the temperature at 20-30 C. The bath was stirred for 2 hours after completing the addition and was then treated with 700 mls. of water. The water layer was removed and the product layer was stripped of naphtha and excess octyl chloride by heating to 170 C. at 20 mm. The tetra noctyl tin was recovered in an amount of 545 gms. (95.2%) and contained 0.2% chlorine.

EXAMPLE 7 Tetra Oleyl Tin Sodium (46 gms., 2.0 mols) was dispersed in 600 gms. of VM and P naphtha as in Example 5. After cooling to 30 C., a solution of di oleyl tin dichloride (346.3 gms., 0.5 mol) in l-chloro octadecene (316.0 gms., 1.1 mols) was slowly added to the sodium dispersion. The mixture was stirred for 2 hours at 25-35 C. and then treated with 400 mls. of water. After removing the water layer, the product layer was stripped of naphtha and excess chloro octadecene by heating to 170 C. at 5 mm. pressure. Tetra oleyl tin was recovered as an amber waxy solid in good yields.

EXAMPLE 8 Tetra n-Butyl Tin The procedure of Example 5 was employed except that there was utilized as the dispersing medium for the sodium a mixture of 200 gms. of VM and P naphtha and 200 gms. of tetra n-butyl tin. The yield of tetra n-butyl tin was 97.5% 'chlorine content 0.32%

EXAMPLE 9 Tetra n-Batyl Tin The same procedure as Example 5 was employed except that 400 gms. of isooctane was used as the dispersing medium, the yield of tetra n-butyl tin was 95.9%, chlorine content 0.51%.

EXAMPLE 10 Tetra (Butyl Benzyl) Tin Sodium (46 gms., 2.0 mols) was dispersed in 600 gms. of toluene according to the procedure of Example 5. After cooling to 50 C. a solution of di n-butyl tin dichloride (152 gms., 0.5 mol) in n-butyl chloride (102 gms., 1.1 mols) was slowly added to the sodium dispersion. After completing the addition, the mixture was stirred for 2 hours at 50-55 C. 300 mls. of water was added, allowed to settle and the aqueous layer removed. The product layer was stripped of toluene and excess butyl chloride by heating to C. at 20 mm. pressure. The yield of product was 201 gms. This product is not tetrabutyl tin because the yield was considerably in excess of theory (theory for tetrabutyl tin is 173.5 gms.). The product was a tetra organotin compound or mixture of such compounds containing both butyl and benzyl groups.

EXAMPLE 11 I Tetra n-Butyl Tin Example 1 was repeated, but there was employedonly 3.0 mols of sodium, 1.6 mols of the butyl chloride and the di n-butyl tin dichloride was replaced by 1.5 mols of tri n-butyl tin chloride. The tetra n-butyl tin was recovered in substantially the same yield as in Example 1.

EXAMPLE 12 Tetra rz-Butyl Tin Example 1 was repeated employing 6 mols of sodium, 4.9 mols of n-butyl chloride and 1.5 mols of n-butyl tin trichloride. Tetra n-butyl tin Was recovered in excellent yield.

EXAMPLE 13 Tetra n-Butyl Tin Example 1 was repeated but the di n-butyl tin dichloride was replaced by 1.5 mols of di n-butyl tin dibromide and the n-butyl chloride was replaced by 3.3 mols of nbutyl bromide. Tetra n-butyl tin was obtained in good yields.

EXAMPLE 14 Tetra Cyclohexyl Tin Example 1 was repeated replacing the tetra n-butyl tin by 520 gms. of naphtha and replacing the di n-butyl tin dichloride by 1.5 mols of dicyclohexyl tin dichloride and replacing the n-butyl chloride by 3.3 mols of cyclohexyl chloride. The tetra cyclohexyl tin was recovered in excellent yield as the final product.

EXAMPLE 15 Tetra Methyl Tin Example 1 was repeated but the di n-butyl tin dichloride was replaced by 1.5 mols of di methyl tin diiodide, the n-butyl chloride was replaced by 3.3 mols of methyl iodide and the tetra n-butyl tin was replaced by an equal amount of tetramethyl tin. The final product obtained was tetramethyl tin in excellent yields.

EXAMPLE 16 1. A process for making organo tin compounds of the formula R Sn where R is a hydrocarbon group selected from the group consisting of alkyl, alkenyl and-benzyl which comprises reacting together in an inert diluent RX, R SnX 'and sodium, wherein X is a halogen selected from the group consisting of chlorine, bromine and iodine, y is a whole number from 1 to 3 inclusive and z' is .4y and wherein the sodium is present in a dispersed form having a particle size of 1 to microns.

2. A process according .to claim rine.

3. A process according to claim 2 wherein all of the Rs are the same hydrocarbon group.

4. A process according to claim 3 wherein R is an alkyl group having 4 to 8 carbon atoms.

5. A process according to claim 4 wherein the particle size of the dispersed sodium is from 1 to 25 microns.

6. A process for making organo tin compounds of the formula R Sn where R is a hydrocarbon group selected from the group consisting ofalkyl, alkenyl and benzyl which comprises reacting together in the presence of R Sn in the starting reaction mixture RX, R SnX and sodium, wherein X is a halogen selected from the group consisting of chlorine, bromine and iodine, y is a whole number from 1 to 3 inclusive and z is 4-y and wherein the sodium is present dispersed in said initial R Sn and 1 wherein X is chlo having a particle size of 1 to 100 microns.

7. A process according to claim 6 wherein the weight of the sodium employed is no more than the weight of the initial R Sn.

8. A process according to claim 6 including an hydrocarbon as an additional diluent.

9. A process according to claim 6 wherein X is chlo-' rme. r

10. A process according to claim 9 wherein all of the Rs are the same hydrocarbon group.

11. A process according to claim 10 wherein R is an alkyl group having 4 to 8 carbon atoms.

12. A process according to claimll wherein the particle size of the dispersed sodium is from 1 to 25 microns and the Weight of the sodium employed is no more than the weight of the initial R Sn.

. 13. A process according to claim 6 wherein the initial diluent consists of the R Sn compound.

14. A process according to claim 1 wherein the initial diluent comprises an aliphatic hydrocarbon.

aliphatic References Cited the file of this patent STATES PATENTS 2,431,038 Harris Nov. 18, 1947 2,570,686 Johnson et al. Oct. 9, 1951 2,805,234 Gloskey Sept. 3, 1957 7 OTHER REFERENCES 

1. A PROCESS FOR MAKING ORGANO TIN COMPOUNDS OF THE FORMULA R4SN WHERE R IS A HYDROCARBON GROUP SELECTED FROM THE GROUP CONSISTING OF ALKYL, ALKENYL AND BENZYL WHICH COMPRISES REACTING TOGETHER IN AN INERT DILUENT RX, RYSNXZ AND SODIUM, WHEREIN X IS A HALOGEN SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE AND IODINE, Y IS A WHOLE NUMBER FROM 1 TO 3 INCLUSIVE AND Z IS 4-Y AND WHEREIN THE SODIUM IS PRESENT IN A DISPERSED FROM HAVING A PARTICLE SIZE OF 1 TO 100 MICRONS. 